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T. A. JACKSON.

METHOD OF INSERTING DIAMOND OE CARBON POINTS IN TOOLS.

No. 336,568. Patented Feb. 23, 1886.

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UNITED STATES PATENT OFFICE.

THADDEUS A. JACKSON, OF NE\V YORK, N. Y.

METHOD OF INSERTING DIAMONDOR CARBON POINTS lN TOOLS.

SPECIFICATION forming part of Letters Patent No. 336,568, dated February 23, 1886.

Application filed November 9, 1885. Serial No.182,265.

T0 on whom it may concern.-

Be it known that I, THADDEUS A. JACKSON, a citizen of the United States, residing at New York, in the county of New York and State of New York, have invented certain new and useful Improvements in Method of Inserting Diamond or Carbon Points in Tools; and I do hereby declare that the following is a full,clear, and exact description of the same, reference being had to the annexed drawing, making a part of this specification, and to the letters and figures of reference marked thereon.

The present invention has reference to the method of setting diamonds or carbon points in metal tools used for cutting and dressing stone, drilling rock, and other analogous purposes, and has direct relation to that class in which the diamond or carbon point is attached by casting the metal upon or around it.

Previous to my invention the great objection to the above-described means of setting the diamond or carbon point was the injury thereto by the contraction of the metal while cooling on the bare surface of said diamond or carbon point, which had a tendency to crush it, especially when its quality was inferior.

Heretofore it has been common to place the diamond, before inserting into the recess of the steel teeth or bits, in a finely-ground bone powder and afterward exposing it to a high degree of heat to remove it from all adhering impurities, to insure a more intimate union of the diamond and steel. The steel teeth or bits are then soft-tempered and allowed to cool, and afterward recesses are cut therein and the diamond inserted and cold metal calked around the same, and then wire wound around the diamond and the tooth or hit, so as to cover the former and protect it from the heat. The diamond is now covered with a bracingpowder, whereby is formed, in connection with the retaining-wire, a protective cover or layer against the action of the heat, after which the teeth or bits are then exposed to such a degree of heat, and brass or copper added, in order to insure a union of the diamond with the steel.

This herein-described method is both expensive and tedious; and the object of the present invention,therefore, is to simplify the (N0 model.)

manner of inserting the diamond or carbon points, whereby the several stages as above described are avoided, and the employment of wire wound around the diamond rendered unnecessary, and at the same time prevent any injury to the diamond by the contraction of the metal around it. These objects I attain by first covering the surface of the diamond or carbon point with a coating of heatresisting substance to form a cushion, and afterward placing the diamond or carbon point thus coated in a mold and casting the metal on or around it, as will be hereinafter described.

In order to better illustrate my invention, I have shown in the drawing the usualholder, A, for a saw-blade or plate having connected thereto by casting the diamond or carbon points B. This holder, as will be seen, has elongated holes through it on line with each of the diamond or carbon points, which I lay no claim to in the present application, it forming the subject of a previous application filed July 16, 1885, Serial No. 171,767, in which this feature is specifically claimed.

In securing the diamond or carbon point in position, it has been usual to place it in a mold and cast the metal forming the holder on or around it, the holder of course being of any desired shape, depending entirely on the use to which the tool is to be applied-such as sawing, drilling, planing, or dressingstone.

Previousto casting the metal around the diamond or carbon point I first cover or envelop the same with a liquid or paste of a heat-resisting substance consisting either of silicate of soda, asbestus, lamp-black, fireclay, or other like ingredient that will, when dry, form a cushion over the surface of the diamond or carbon point, and that will resist the heat from the molten metal, the coating ICO Having now fully described my invention, or around it, substantially as and for the pur- 10 what I claim as new, and desire to secure by pose set forth. Letters Patent, is In testimony that I claim the above I have The method of securing diamonds or carbon hereunto subscribed my name in the presence 5 points in 'metallic holders, consisting of first of two witnesses.

covering the surface of said diamond or car- THADDEUS A. JACKSON. bon point with a coating of a heatresisting XVitnesses: substance to form a cushion, and afterward L. L. MILLER,

placing it in a mold and casting the metal on 1 M. P. CALLAN. 

